We had everything translated because we are submitting all documents to the NVC first and they are forwarding to the embassy. I know some people bring documents with them though but I don't know how that works. Here's a link to the official government site that might be helpful.
Thank you. It says they do not need to be translated, but now I'm wondering what documents are needed. :/ Maybe they will tell us when his interview is set up and he receives the letter.